How to keep well : a text-book of health for use in the lower grades of schools with special reference to the effects of alcholic drinks, tobacco and other narcotics on the bodily life . Fig. 25. —Vertical S<_ciion througha Tooth lodged in its Socket. ^MOLARS Fig. 26. — The Teeth. hard pressed against the roof of the mouth, and thenswallowed. During this time the food is well mixedwith the fluid of the mouth, called saliva, which flowsfrom a number of little spongy organs inside themouth. Probably you have had the mumps, or atleast have seen some friend who has had the is it ?
How to keep well : a text-book of health for use in the lower grades of schools with special reference to the effects of alcholic drinks, tobacco and other narcotics on the bodily life . Fig. 25. —Vertical S<_ciion througha Tooth lodged in its Socket. ^MOLARS Fig. 26. — The Teeth. hard pressed against the roof of the mouth, and thenswallowed. During this time the food is well mixedwith the fluid of the mouth, called saliva, which flowsfrom a number of little spongy organs inside themouth. Probably you have had the mumps, or atleast have seen some friend who has had the is it ? Why, sometimes these little organs, of 68 HOW TO KEEP WELL which there is one under each ear, become inflamed,and grow large; and this is known as the mumps. The saliva wets the food, and so makes it easier toswallow. It has, besides, another very important workto do : it acts on the starchy part of the food, chan-ging some of it into sugar. You know that a piece ofbread grows sweet in the mouth when it is well wet. Fig. 27. — Section of Jaws, showing the Milk and the Second Teeth. with saliva. This work of the saliva is important, elsestarch could not be dissolved, and therefore would dous no good as food, while sugar is readily dissolved. When we are not eating, the saliva flows only insmall quantities, just enough to keep the mouth com-fortably moist ; but when we begin to eat, these littlefactories do a brisk business, and pour into the moutha large quantity, about half a pint, it is said, at a single DIGESTION, AND HOW IT GOES ON 69 meal. The sight, or even the thought, of a savorydish, will make the saliva flow, or, as we say, makethe mouth water. The sight of a piece of meat willmake the saliva run out of a hungry dogs mouth. Runyour finger to and fro in the mouth several times, andnotice how quickly the saliva flows. Smoking or chewing tobacco causes an undueamount of saliva to flow from these glands, thusmaking the mouth dry. The constant spitting oftobacco-juice
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecthygiene, bookyear1901
